MEPS 432:257-268 (2011)  -  doi:10.3354/meps09145

Population structure and individual movement of southern right whales around New Zealand and Australia

E. Carroll1,*, N. Patenaude2, A. Alexander1,3, D. Steel3, R. Harcourt4, S. Childerhouse5, S. Smith6, J. Bannister7, R. Constantine1, C. Scott Baker1,3

1Laboratory of Molecular Ecology and Evolution, School of Biological Sciences, University of Auckland, Auckland 1010, New Zealand
2LGL Limited, Environmental Research Associates, King City, Ontario L7B 1A6, Canada
3Marine Mammal Institute and Department of Fisheries and Wildlife, Hatfield Marine Science Center, Oregon State University, Newport, Oregon 97365, USA
4Marine Mammal Research Group, Graduate School of the Environment, Macquarie University, Sydney, New South Wales 2109, Australia
5Australian Marine Mammal Centre, Australian Antarctic Division, DSEWPC, Kingston, Tasmania 7050, Australia
6New Zealand Department of Conservation, Aquatic and Threats Unit, Wellington 6143, New Zealand
7Western Australian Museum, Locked Bag 49, Welshpool DC, Western Australia 6986, Australia

ABSTRACT: During the last 2 centuries, southern right whales Eubalaena australis were hunted to near extinction, and an estimated 150000 were killed by pre-industrial whaling in the 19th century and illegal Soviet whaling in the 20th century. Here we focus on the coastal calving grounds of Australia and New Zealand (NZ), where previous work suggests 2 genetically distinct stocks of southern right whales are recovering. Historical migration patterns and spatially variable patterns of recovery suggest each of these stocks are subdivided into 2 stocks: (1) NZ, comprising NZ subantarctic (NZSA) and mainland NZ (MNZ) stocks; and (2) Australia, comprising southwest and southeast stocks. We expand upon previous work to investigate population subdivision by analysing over 1000 samples collected at 6 locations across NZ and Australia, although sample sizes were small from some locations. Mitochondrial DNA (mtDNA) control region haplotypes (500 bp) and microsatellite genotypes (13 loci) were used to identify 707 individual whales and to test for genetic differentiation. For the first time, we documented the movement of 7 individual whales between the NZSA and MNZ based on the matching of multilocus genotypes. Given the current and historical evidence, we hypothesise that individuals from the NZ subantarctic are slowly recolonising MNZ, where a former calving ground was extirpated. We also suggest that southeast Australian right whales represent a remnant stock, distinct from the southwest Australian stock, based on significant differentiation in mtDNA haplotype frequencies (FST = 0.15, p < 0.01; ΦST = 0.12, p = 0.02) and contrasting patterns of recovery. In comparison with significant differences in mtDNA haplotype ­frequencies found between the 3 proposed stocks (overall FST = 0.07, ΦST = 0.12, p < 0.001), we found no significant differentiation in microsatellite loci (overall FST = 0.004, G’ST = 0.019, p = 0.07), suggesting ongoing or recent historical reproductive interchange.

KEY WORDS: Southern right whale · Eubalaena australis · mtDNA · Microsatellite · Population structure

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Cite this article as: Carroll E, Patenaude N, Alexander A, Steel D and others (2011) Population structure and individual movement of southern right whales around New Zealand and Australia. Mar Ecol Prog Ser 432:257-268

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